There’s growing evidence that regular exposure to man-made
“forever” chemicals, which are used in a variety of household
products, are linked to rising cancer rates.
A new study that examined the correlation between liver cancer
and the presence of these chemicals in humans found that people
with the highest levels of exposure have 350% greater odds of
eventually developing the disease.
The term “forever” chemicals refers to the more than 4,700
available types of perfluoroalkyl and polyfluoroalkyl
substances, or PFAS, used widely across manufacturing industries
— named as such because the substances degrade very slowly and
build up over time, in soil, drinking water and in the body.
PFAS were first introduced in the 1930s as a revolutionary
material used in the creation of nonstick cookware — hello,
Teflon — and soon adapted to all sorts of products and packaging
— from construction materials to cosmetics — that benefit from
its liquid- and fire-resistant properties, as noted by the
Centers for Disease Control and Prevention.
Though incredibly useful, such chemicals have since been linked
to the onset of cancer and other illnesses in lab animals.
Following strong anecdotal evidence that perfluorooctanesulfonic
acids (PFOS) alongside another common substance called
perfluorooctanoic acid (PFOA) were making consumers sick, the
Environmental Protection Agency in 2006 ordered eight
multinational manufacturing corporations represented in the US
to phase out the use of such chemicals. Nevertheless, as their
nickname implies, PFOS and PFOA are still being detected in
foreign products, in groundwater and in people.
The current study, published in JHEP Reports, is the first to
show a clear association between any PFAS and nonviral
hepatocellular carcinoma (the most common type of liver cancer)
in humans, too.
“This builds on the existing research, but takes it one step
further,” said Jesse Goodrich, a postdoctoral public health
researcher at Keck School of Medicine, in a University of
Southern California news release. “Liver cancer is one of the
most serious endpoints in liver disease and this is the first
study in humans to show that PFAS are associated with this
Showing an association between PFAS and cancer in humans hasn’t
been easy for scientists.
“Part of the reason there has been few human studies is because
you need the right samples,” added Keck School of Medicine
professor Veronica Wendy Setiawan. “When you are looking at an
environmental exposure, you need samples from well before a
diagnosis because it takes time for cancer to develop.”
To make this leap, researchers were given access to the
Multiethnic Cohort Study database, which entails a survey of
cancer development in more than 200,000 residents of Hawaii as
well as Los Angeles, Calif., conducted by the University of
Their search was narrowed to 100 survey participants — 50 of
them with liver cancer and 50 without — whose available blood
and tissue samples were sufficient for analysis. Researchers
were looking for traces of “forever” chemicals present in the
body before the group with cancer became ill.
They reportedly found several types of PFAS among participants,
with PFOS appearing most prominently among those in the group
with liver cancer. Indeed, their investigation revealed that
those who fell in the top 10% of PFOS exposure were 4.5 times
more likely to develop hepatocellular carcinoma when compared to
those with the least exposure.
The clear link between PFAS and cancer in humans is crucial to
further study on how these chemicals interfere with biological
processes. Per the current findings, USC scientists now believe
that high concentrations of PFOS in some subjects had impaired
the liver’s ability to metabolize glucose, bile acid and
branched-chain amino acids, resulting in unhealthy levels of fat
accumulation in the organ, otherwise known as nonalcoholic fatty
liver disease — a high-risk factor for liver cancer.
That’s why many scientists agree it’s no coincidence that the
advent and widespread use of “forever” chemicals correlates with
a rise in liver disease, cancer and other illnesses.
“We believe our work is providing important insights into the
long-term health effects that these chemicals have on human
health, especially with respect to how they can damage normal
liver function,” said study author Dr. Leda Chatzi. “This study
fills an important gap in our understanding of the true
consequences of exposure to these chemicals.”